nest-cron-manager

Overview

nest-cron-manager is a TypeScript-based library designed to manage and execute cron jobs efficiently. It provides a robust interface for scheduling, executing, and logging cron jobs with support for Redis-based locking mechanisms to ensure job execution integrity.

Installation

To install the package, use npm:

npm install nest-cron-manager

Usage

Prerequisites

Before using the nest-cron-manager library, ensure the following requirements are met:

• Install ioredis,@nestjs/config and typeorm/mongoose packages:

  npm install ioredis typeorm @nestjs/config

• Create CronConfig and CronJob models in your project which implement the CronConfigInterface and CronJobInterface respectively.

  // src/cron-config/cron-config.model.ts
  
  import { JobType } from 'nest-cron-manager';
  import {
    CronConfig as CronConfigInterface,
    CronJob as CronJobInterface,
  } from 'nest-cron-manager/types';
  import { Column, Entity, OneToMany, PrimaryGeneratedColumn } from 'typeorm';
  import { CronJob } from './cron-job.model';
  
  @Entity({ name: 'cron_configs' })
  export class CronConfig implements CronConfigInterface {
    @PrimaryGeneratedColumn()
    id: number;
  
    @Column({ unique: true })
    name: string;
  
    @Column({ nullable: true, default: JobType.INLINE })
    jobType?: JobType; // inline, method, query
  
    @Column({ default: false })
    enabled: boolean;
  
    @Column({ nullable: true, type: 'jsonb' })
    context?: any;
  
    @Column({ nullable: true })
    cronExpression?: string;
  
    @Column({ nullable: true })
    query?: string;
  
    @Column({ nullable: true, default: false })
    dryRun?: boolean;
  
    @Column({ nullable: true })
    deletedAt?: Date;
  
    @OneToMany(() => CronJob, (cronJob) => cronJob.config)
    jobs: CronJob[];
  }

  // src/cron-config/cron-job.model.ts
  
  import { Column, Entity, Index, ManyToOne, PrimaryGeneratedColumn } from 'typeorm';
  import { CronConfig } from './cron-config.model';
  import { CronJob as CronJobInterface } from 'nest-cron-manager/types';
  
  @Entity({ name: 'cron_jobs' })
  export class CronJob implements CronJobInterface {
    @PrimaryGeneratedColumn()
    id: number;
  
    @Index()
    @ManyToOne(() => CronConfig, (config) => config.jobs)
    config: CronConfig;
  
    @Column({ nullable: true, type: 'jsonb' })
    result?: any;
  
    @Column()
    startedAt: Date;
  
    @Column({ nullable: true })
    completedAt: Date;
  
    @Column({ nullable: true })
    failedAt: Date;
  }

• NB: You can implement whatever network and serialization protocol you want to use. For the purpose of this example, we will use gRPC.

• Create these protobuf service definitions: CreateCronConfig and UpdateCronConfig in your project. For this example, we will use the inventory service.

  syntax = "proto3";
  
  package cron;
  
  service InventoryService {
    /**
    * Create new inventory cron config. Cron config name must match the function name
    */
    rpc CreateCronConfig(cron.CreateCronConfigRequest) returns (cron.CreateCronConfigResponse) {
        option (google.api.http) = {
            post: "/v1/inventory/cron-config"
            body: "*"
        };
    };
  
    /**
    * Update inventory cron config. Cron config name must match the function name
    */
    rpc UpdateCronConfig(cron.UpdateCronConfigRequest) returns (cron.UpdateCronConfigResponse) {
        option (google.api.http) = {
            put: "/v1/inventory/cron-config/{id}"
            body: "*"
        };
    };
  }
  

• Create a CronConfigController in your project to handle the creation and updating of cron configurations.

  // src/cron-config/cron-config.controller.ts
  
  import { CronManager } from 'nest-cron-manager';
  import { Controller } from '@nestjs/common';
  import { GrpcMethod } from '@nestjs/microservices';
  import {
    CreateCronConfigRequest,
    UpdateCronConfigRequest,
  } from '../../generated_ts_proto/inventory/inventory_pb';
  
  @Controller()
  export class CronConfigController {
    constructor(private readonly cronManager: CronManager) {}
  
    @GrpcMethod('InventoryService', 'CreateCronConfig')
    async createCronConfig(data: CreateCronConfigRequest.AsObject) {
      return this.cronManager.createCronConfig(data);
    }
  
    @GrpcMethod('InventoryService', 'UpdateCronConfig')
    async updateCronConfig(data: UpdateCronConfigRequest.AsObject) {
      return this.cronManager.updateCronConfig(data);
    }
  }

• Create a CacheService in your project and ensure it implements a getClient method.

  import { Injectable } from '@nestjs/common';
  
  @Injectable()
  export class CacheService {
    getClient(): Redis {
      return this.client;
    }
  }

• Implement nestjs config service in your project.

  import { registerAs } from '@nestjs/config';
  
  export default registerAs('config', () => ({
    cronManager: {
      enabled: process.env.CRON_MANAGER_ENABLED,
      querySecret: process.env.CRON_MANAGER_QUERY_SECRET,
    },
  }));

Instantiating the CronManager class

Create an instance of CronManager by passing the required dependencies specified in CronManagerDeps:

// src/cron-config/cron-config.module.ts

import { CacheModule } from '@/cache/cache.module';
import { CacheService } from '@/cache/cache.service';
import { Logger, Module } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { getRepositoryToken, TypeOrmModule } from '@nestjs/typeorm';
import { CronManager } from 'nest-cron-manager';
import { Repository } from 'typeorm';
import { CronConfigController } from './cron-config.controller';
import { CronConfig } from './cron-config.model';
import { CronJob } from './cron-job.model';

@Module({
  controllers: [CronConfigController],
  imports: [TypeOrmModule.forFeature([CronConfig, CronJob]), CacheModule],
  providers: [
    {
      provide: CronManager,
      useFactory: (
        configService: ConfigService,
        cronConfigRepository: Repository<CronConfig>,
        cronJobRepository: Repository<CronJob>,
        redisService: CacheService,
      ) =>
        new CronManager({
          logger: new Logger(CronManager.name),
          configService,
          cronConfigRepository,
          cronJobRepository,
          redisService,
          ormType: 'typeorm',
        }),
      inject: [
        ConfigService,
        getRepositoryToken(CronConfig),
        getRepositoryToken(CronJob),
        CacheService,
      ],
    },
  ],
  exports: [CronManager],
})
export class CronConfigModule {}

Executing cron jobs

Depending on the specified jobType when creating your cronConfig, there are three different ways the cronManager may execute the job:

1. inline: The cron job will execute a inline function passed to the handleJob method of the CronManager class.

   curl -X 'POST' \
     'http://localhost:3000/v1/inventory/cron-config' \
     -H 'accept: application/json' \
     -H 'Content-Type: application/json' \
     -d '{
     "name": "doSomething",
     "jobType": "inline",
     "enabled": true,
     "context": "{
       \"distributed\": true,
       \"ttl\": 20,
       \"[key]\":\"value\"
     }"
   }'

   The context field is optional and can be used to pass additional configuration to the cron job.

   In this example, we are passing a distributed flag to indicate that the job should be distributed across multiple instances of the application.

   We are also passing a ttl field to specify the time to live for the job lock in seconds.

   Asides from the distributed and ttl fields which are used internally, you can pass any other configuration you want to the cron job which can be accessed in the job handler function.

   NB: The context field must be a valid JSON string.

   To execute cron jobs, use the handleJob method of the CronManager class:

   NB: While you could call the handleJob of the cronManager anywhere in your project, it is recommended to define all handlers in the CronJobService class. Benefits of this approach:

   • Ensure unique job names across the application.
   • Easily switch a handler function between the inline and method job types
   • Manage all job handlers in one place

   Below is an example of how to execute a cron job using the handleJob method:

   import { CronManager } from 'nest-cron-manager';
   import { Cron, CronExpression } from '@nestjs/schedule';
   
   @Injectable()
   export class CronJobService {
     constructor(private readonly cronManager: CronManager) {}
   
     @Cron(CronExpression.EVERY_5_MINUTES)
     async doSomething() {
       await this.cronManager.handleJob(
         'doSomething',
         async (context: Record<string, any>, config: Record<string, any>) => {
           const events = [];
           // Other variables
   
           try {
             // Perform some operation
   
             // Log success
             events.push({
               action: 'Operation 1',
               status: 'success',
               error: null,
             });
   
             // Perform another operation
   
             // Log success
             events.push({
               action: 'Operation 2',
               total: 5,
             });
   
             // Return events.
             return events;
           } catch (error) {
             // Handle error
   
             // Log error
             events.push({
               status: 'error',
               error: error.message,
             });
   
             // Rethrow error. This is important to ensure the job is marked as failed
             throw new Error(JSON.stringify(events));
           }
         },
       );
     }
   }

2. method: The cron job will execute a method defined on your CronJobService class. The method name MUST match the cronConfig name and you must provide the cronExpression.

    curl -X 'POST' \
      'http://localhost:3000/v1/inventory/cron-config' \
      -H 'accept: application/json' \
      -H 'Content-Type: application/json' \
      -d '{
      "name": "doSomething",
      "jobType": "method",
      "enabled": false,
      "cronExpression": "0 0 * * *",
    }'

   Below is an example of how you may define your method on a CronJobService class:

   //...
   
   @Injectable()
   export class CronJobService {
     constructor(private readonly cronManager: CronManager) {}
   
     async doSomething() {
       // Perform some operation
     }
   }
   
   //...

   NB: The method name must match the cronConfig name.

3. query: The cron job will execute a query provided during the creation of the cronConfig. The query must be a valid SQL query. Your query will be encrypted at rest with the query secret provided in your app config and will only be decrypted at runtime using the same secret.

    curl -X 'POST' \
      'http://localhost:3000/v1/inventory/cron-config' \
      -H 'accept: application/json' \
      -H 'Content-Type: application/json' \
      -d '{
      "name": "doSomething",
      "jobType": "query",
      "enabled": false,
      "query": "SELECT * FROM users",
    }'